Recording defect substitution method for a disc-shaped recording medium, and a recording and reproducing apparatus for a disc-shaped recording medium

ABSTRACT

In a recording and reproducing apparatus for a disc-shaped recording medium, and a defect substitution method for a disc-shaped recording medium, whether reproduction of recorded data is good is determined by sector unit and not by product code unit, defective sector discrimination is performed by sector unit, and only sectors determined defective are alternately recorded, when using a recording format in which data that is error detection and correction coded with a product code is segmented and recorded to a plurality of sectors.

This is a Rule 1.53(b) Divisional Application of Ser. No. 09/598,250,filed Jun. 21, 2000, now U.S. Pat. No. 6,301,220, which is a Rule1.53(b) Divisional Application of Ser. No. 09/142,910, filed Sep. 18,1998, now U.S. Pat. No. 6,134,214.

FILED OF THE INVENTION

The present invention relates to a defect substitution method of adisc-shaped recording medium having a sector structure, and to anapparatus for recording and reproducing data on a disc-shaped recordingmedium using said defect substitution method, and more specificallyrelates to an optical disc defect management method of an optical discin a recording system in which error detection and correction codingspans a plurality of sectors, and to an optical disc recording andreproducing apparatus.

DESCRIPTION OF THE PRIOR ART

High speed random access is possible with disc-shaped recording media,and a high recording density can be achieved by formatting a disc with anarrow data track pitch and bit pitch. Disc-shaped recording media canbe generally categorized based on differences in the applicablerecording method as either a magnetic disc or optical disc, and can befurther classified as either a fixed type or removable type media basedon differences in the method whereby the medium is mounted in therecording/reproducing apparatus during use. The smallest recording unitof the physical recording area to which data is generally recorded ondisc-shaped recording media is called a “sector.” Sectors that cannot beused for data storage also occur in disc-shaped recording media as aresult of defects during manufacture or damage occurring aftermanufacture. In addition to data writing errors occurring as a result ofwriting data sectors that are defective as a result of damage to thedisc-shaped recording medium itself, data writing errors attributable tothe operating environment can also occur as described below.

Optical discs, of which the DVD is typical, have been widely used inrecent years as a large capacity recording medium because of their highrecording density. Further advances in recording density have also beenachieved to further increase storage capacity. Optical discs, however,are typically manufactured from low rigidity materials such aspolycarbonate, and even disc deflection resulting from the dead weightof the disc cannot be ignored. In addition, this type of optical disc iscommonly used as a replaceable, removable recording medium. For use, thedisc is inserted into a recording and reproducing apparatus and mountedon a rotating spindle, and the positioning precision of the disctherefore cannot be assured.

It is also common to directly insert optical discs into the recordingand reproducing apparatus without housing the disc in a protective case.Even when used housed in such a protective case, however, the entirerecording medium is exposed during recording and reproducing because theprotective case is not airtight. That is, optical disc recording mediahave essentially no shielding against the ambient environment. It shouldbe noted that the problems specific to optical recording media reside inthe point that these media are different from the hard disc recordingmedia, including both low recording density fixed discs and removablehard discs, which are also a magnetic storage medium.

In addition to problems associated with their rigidity, mountingprecision, and low airtightness, when an optical disc recording mediumis inserted into a recorder and recorded or played, normal recording andreproducing can be inhibited by variations in the relative position tothe optical pickup, or by foreign matter in the air interfering with thelaser from the optical pickup. In such cases, data reading and writingcan be obstructed through a wide band of the recording area, and burstmode recording and reproduction errors occur easily, as a result of thenarrow track pitch and dot pitch enabling high density recording, evenif there are no disc defects or damage to the information sector of theoptical disc recording medium. While such burst-mode recording andreproducing problems occur easily in optical disc recording media, theyare also found in the above-noted magnetic recording media and arecommon to all types of disc-shaped recording medium.

“Recording defect” is a general term for the inability to record as aresult of a defect or damage to the recording medium itself or theconditions under which the disc is used. If a recording defect occurswhen recording data to a particular sector, data is recordedcontinuously to the recording medium by saving the data to a reservedrecording sector area, which is reserved separately from the normal datarecording sectors, no matter what the cause of the recording defect.This operation of recording to a reserved sector area data that shouldbe recorded to the sector in which a recording defect occurred is called“alternative recording,” and the reserved sector area used foralternative recording is called an “alternative area.”

In consideration for the above-noted problems, an object of the presentinvention is therefore to provide a defect management method whereby thesize of the required alternative area can be suppressed and adisc-shaped recording medium can be efficiently used, and to provide arecording and reproducing apparatus for a disc-shaped recording medium.

DISCLOSURE OF THE INVENTION

A disc-shaped recording medium recording and reproducing apparatus forrecording data by sector unit to a disc-shaped recording medium having astructure with a plurality of recording sectors, said disc-shapedrecording medium recording and reproducing apparatus characterized bycomprising: a coding means for error detection and correction codingsaid data twice, in row and column directions, and segmenting said datainto sector units; a means for recording data coded in sector units to asector in a first recording area of said disc-shaped recording medium; adefective sector discrimination means for reproducing said sector todiscriminate whether the sector is a defective sector; and a defectivesector substitution means for, when said sector is determined to be adefective sector, recording data recorded to a defective sector to analternative sector in a second recording area disposed on saiddisc-shaped recording medium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the recording surface of an optical disc recordingmedium according to an embodiment of the present invention;

FIG. 2 is a view of the logic structure of a recording area of theoptical disc recording medium shown in FIG. 1;

FIG. 3 is an illustration showing the relationship between a sector anderror detection and correction coded data according to an embodiment ofthe present invention;

FIG. 4 is a view showing an interleaving method for error detection andcorrection coded data according to an embodiment of the presentinvention;

FIG. 5 is a block diagram showing the configuration of an optical discrecording medium recording and reproducing apparatus according to anembodiment of the present invention;

FIG. 6 is a view used to describe the defective sector substitutionprocess according to a first embodiment of the present invention;

FIG. 7 is a view used to describe the defective sector substitutionprocess according to a second embodiment of the present invention;

FIG. 8 is a flow chart showing the operation of the optical discrecording medium recording and reproducing apparatus shown in FIG. 5;

FIG. 9 is a flow chart showing the detailed operation of thereproduction control step shown in FIG. 8;

FIG. 10 is a flow chart showing the detailed operation of the recordingcontrol step shown in FIG. 8;

FIG. 11 is a flow chart showing the detailed operation of the targetaddress extraction step shown in FIG. 8;

FIG. 12 is a flow chart showing the detailed operation of the PDL-basedaddress conversion step shown in FIG. 11;

FIG. 13 is a flow chart showing the detailed operation of the SDL-basedaddress conversion step shown in FIG. 11;

FIG. 14 is a flow chart showing the detailed operation of the sectorsubstitution processing step shown in FIG. 8 according to a firstembodiment; and

FIG. 15 is a flow chart showing the detailed operation of the sectorsubstitution processing step shown in FIG. 8 according to a secondembodiment.

BEST MODE FOR ACHIEVING THE INVENTION

A defect substitution method and a recording and reproducing apparatusbased on a working example of the present invention are described belowwith reference to the accompanying figures using an optical discrecording medium as exemplary of a disc-shaped recording medium,including magnetic recording media.

The physical format of a recording surface of an optical disc recordingmedium written by a recording and reproducing apparatus according to thepresent invention is shown in FIG. 1. This optical disc recording medium(hereafter simply “optical disc”) is segmented, in sequence from theinside circumference side of the disc, into a lead-in area LiA, a dataarea DuA, and a lead-out area LoA. Management information for datarecorded to the optical disc, and including information for defectmanagement, is recorded to the lead-in area LiA and lead-out area LoA.User data is recorded to the data area DuA. Each track, whichcorresponds in this example to one revolution of the disc, is dividedinto plural sectors. Each sector comprises an ID part containing apreformatted sector address, and a data recording part UD to which datais written. The sector address written to the ID part is lowest in thesectors at the inside circumference and increases sequentially at eachsector.

The data area DuA in the present example is formatted for zone-constantlinear velocity (ZCLV) access, that is, the data area DuA is segmentedinto a plurality of zones ZN0 to ZNm (where m is an integer), the numberof sectors per track in a given zone ZN increases from the insidecircumference to the outside circumference of the disc, and therotational velocity of the disc is adjusted for each zone to achieve aconstant transfer rate. In the present example, there are 8 sectors pertrack in zone ZN0 and the lead-in area LiA, 9 sectors per track in zoneZN1, and 16 sectors per track in zone ZNm and the lead-out area LoA.

The logical format of a recording surface of the optical disc shown inFIG. 1 is shown in FIG. 2. The lead-in area LiA is segmented into twoareas, defect management areas DMA1 and DMA2, to which managementinformation for defect management is recorded. The data area DuA issegmented into a plurality of zones ZN0 to ZNm. Each zone ZN is dividedinto a data sector area ADS to which user data is written, and a sparesector area ASS, which is used as an alternative sector when a defectivesector is found.

The lead-out area LoA is segmented into two areas, defect managementareas DMA3 and DMA4, to which management information for defectmanagement is recorded. For increased reliability, the same informationis recorded to a primary defect list PDL and a secondary defect list SDLin each of the defect management areas DMA1, DMA2, DMA3, and DMA4. Theprimary defect list PDL contains defective sector addresses PDSA0 toPDSAn (where n is an integer) in sequence from low to high address wherethe defective sector addresses PDSA0 to PDSAn are defect managementinformation used for a slipping method described below. The secondarydefect list SDL contains defective sector addresses SDSA0 to SDSAp(where p is an integer) and alternative sector addresses SSSA0 to SSSApin sequence from low to high address where defective sector addressesSDSA0 to SDSAp are defect management information used for a linearplacement method described below.

An effective method of handling burst-mode read/write errors in anoptical disc thus formatted is to increase the interleave length indepth of the error detection and correction code, disperse burst-modeerrors to the level of random errors with respect to the error detectionand correction code, and thereby improve data reproduction reliability.For example, in an optical disc recording medium provided for recordingand reproducing digitally compressed image data, 2 KB of user data isrecordable per sector, and the error detection and correction code iscompiled for blocks of 16 sectors, thereby more deeply interleavingerror detection and correction. More specifically, the data is formattedso as to increase the interleave length in depth by error detection andcorrection coding each 32 KB block of user data twice, that is, in rowand column directions, creating coded data blocks each containing atotal of about 38 KB of data, including error detection and correctioncoding parity data.

While a read-only optical disc recording medium (hereafter a “ROM disc”)containing prerecorded data can only be read, user data can be recordedusing a recording device (hereafter “drive”) to an optical discrecording medium that can both be read from and written to (hereafter a“RAM disc”). For the reasons described above, however, it is not alwayspossible to completely record the data to be recorded. That is, it isgenerally difficult to ensure normal recording of data to all sectorsbecause of defects in the recording medium occurring during or aftermanufacture, deflection of the medium, variations in the positioningprecision inside the drive, or dust and other foreign matter.

The drive therefore generally has a defect substitution function forapplying a read verification process whereby the recorded data isreproduced to confirm that normal reproduction is possible, andsubstituting an alternate recording area when a writing error isdetected. Writing error detection is typically performed during theprocess of decoding the error detection and correction code duringreproduction, and the unit used for this substitution process istherefore the error detection and correction coding unit. With amagneto-optical disc used for recording code data, for example, thedefect substitution process is applied in 512 byte blocks, the unit usedfor error detection and correction coding, or in units of a singlesector, which corresponds to 1 KB of user data.

When the error detection and correction code is the unit for the defectsubstitution process, a write error in one place requires the entirecorresponding error detection and correction code to be alternatelyrecorded, and when an error correction code with a deep interleave isused, it is necessary to reserve more alternate recording areas. As aresult, the ability to effectively utilize the recording area of therecording medium can be impaired. For example, when a block of 16sectors is the unit for one error detection and correction code in a RAMdisc as described above, all 16 sectors must be substituted when a writeerror occurs in any one sector, and in a worst-case scenario a 16-sectoralternative area is required for each defective sector. The presentinvention therefore further provides an error detection and correctioncoding method and apparatus for minimizing the alternative area requiredfor a single writing error, and improving the utilization efficiency ofthe recording medium, as described in detail below with reference toFIG. 3 to FIG. 15.

FIG. 3 shows the relationship between a sector and the error detectionand correction coding data according to the present invention. The codeddata for one error detection and correction code is allocated andrecorded to the data recording areas UD in 16 sectors. As describedabove, address information is prerecorded to the ID part, and user datais recorded to the data recording area UD.

An interleaving method for an error detection and correction codeaccording to the present invention is shown in FIG. 4. The structure ofthe error detection and correction code is shown on the left side ofFIG. 4, and the method of interleaving the error detection andcorrection code for recording to 16 sectors as shown in FIG. 3 is shownon the right side of the figure.

As shown in the figure, the error correction code shown on the left sidecomprises approximately 32 KB of data 3, which contains Data 0 to Data15, each approximately 2 KB, including 2 KB of user data, a CRC forerror detection, and control data for such as copyright protection, andis arranged in a row and column pattern containing 172 bytes per row and192 bytes per column. Reference numeral 4 denotes a C1 parity whichcontains parity blocks C1-0 to C1-15, which are generated by errordetection and correction coding data 3 in rows, and adding a 10-byteparity code to each row. Reference numeral 5 denotes a C2 parity whichcontains parity blocks C2-0 to C2-15, which are generated by errordetection and correction coding data 3 in columns, and adding a 16-byteparity code for each column.

Thus, as described above, a product code is used for error detection andcorrection coding approximately 32 KB of data in both row and columndirections. In addition, both the row and column error detection andcorrection codes are formatted for high reliability error correctionusing a Reed-Solomon code to ensure a sufficiently long interleavelength of approximately 38 KB, including parity data, and effectivecorrection of both random errors and burst errors.

In the structure of the interleaved error detection and correction codeshown on the right, data 3 is segmented row-wise into 16 blocks fromData 0 to Data 15. The C1 parity 4 is divided row-wise into 16 blocksfrom C1-0 to C1-15. The C2 parity 5 is segmented row-wise into 16 blocksfrom C2-0 to C2-15. The data recorded to each sector comprises one blockof segmented data 3, one block of C1 parity 4, and one block of C2parity 5. The recording data of one sector is then recorded to the datarecording area UD of 16 sectors in m row direction.

In other words, row 1 of Data 0, row 1 of C1-0, row 2 of Data 0, row 2of C1-0, and so on to row 12 of Data 0, row 12 of C1-0, and C2-0 arerecorded to the first sector. Row 1 of Data 1, row 1 of C1-1, row 2 ofData 1, row 2 of C1-1, and so on to row 12 of Data 1, row 12 of C1-1,and C2-1 are recorded to the second sector. Subsequent sectors aresimilarly recorded until the 16th sector where row 1 of Data 15, row 1of C1-15, row 2 of Data 15, row 2 of C1-15, and so on to row 12 of Data15, row 12 of C1-15, and C2-15 are recorded.

As thus described above, 32 KB of user data is product coded, andrecorded distributed across 16 sectors.

The configuration of a recording and reproducing apparatus according tothe present invention for use with a disc-shaped recording medium andwith application to an optical disc is shown in FIG. 5. The apparatuscomprises an optical disc 8, disc motor 9, optical head 10, laser drivecircuit 11, modulator/demodulator 12, error detector and corrector 13,RAM 14, interface controller 15, amplifier/digitizer 16, focus trackingcontroller 17, and control CPU 18. The disc motor 9 rotates the opticaldisc 8. The optical head 10 comprises an optical lens and semiconductorlaser, and accomplishes reading data from and writing data to theoptical disc 8. The laser drive circuit 11 drives the laser of theoptical head 10. During recording, the modulator/demodulator 12digitally modulates the data to a form suitable for recording, andduring reproduction demodulates the data. The error detector andcorrector 13 error detection and correction codes the data duringrecording, and during reproduction decodes the coded data and applieserror detection and correction. RAM 14 is used as a data buffer andworking RAM of the error detector and corrector 13. The interfacecontroller 15 controls interfacing with a host computer through anexternal input terminal Ti and output terminal To. Theamplifier/digitizer 16 amplifies and digitizes the reproduced signal.The focus tracking controller 17 tracks the optical head 10 to thetarget track, and focuses the laser beams on the recording surface.

The control CPU 18 is the control device providing overall control ofthe optical disc recording and reproducing apparatus, and comprises atarget address extractor 31, reproduction controller 32, commandcontroller 33 for such operations as command analysis, a recordingcontroller 34, and a sector substitution processor 35.

The target address extractor 31 determines the sector address forreading or writing. The reproduction controller 32 reproduces data froma sector. The command controller 33 for such operations as commandanalysis performs such operations as analyzing commands from a hostcomputer. The recording controller 34 controls recording for writingdata to a sector. The sector substitution processor 35 handles alternaterecording in sector units when a defective sector is found duringrecording. The control CPU 18 is preferably a microprocessor whereby thefunctions of the component units thereof can be accomplished insoftware.

The data recording operation by an optical disc recording andreproducing apparatus thus constructed is described briefly below.

User data S19 sent from a host computer is passed by the interfacecontroller 15 and temporarily stored to the RAM 14, which is a workingbuffer for the error detector and corrector 13. Note that user data S19corresponds to Data 0 to Data 15 described above with reference to FIG.4. The error detector and corrector 13 generates the C1 parity 4 and C2parity 5 by means of row-wise coding, that is, C1 coding, andcolumn-wise coding, that is C2 coding. The control CPU 18 notifies thefocus tracking controller 17 of the target track, and the focus trackingcontroller 17 thus moves the optical head 10 to the target track. Thelight beam emitted from the optical head. 10 is reflected by the opticaldisc 8, producing a read beam that is supplied to theamplifier/digitizer 16.

The read beam is modulated according to the pits and lands of the IDpart to which the prerecorded address information is recorded. In thedata recording area UD where data is recorded, the read beam ismodulated according to the variations in amount of reflected lightproduced by the recording marks. The modulated read beam is thusconverted by the amplifier/digitizer 16 to digital read signal S20,which is supplied to the modulator/demodulator 12. Themodulator/demodulator 12 detects the address of the target sector fromthe digital read signal S20, and digitally modulates the coded data S21from the error detector and corrector 13. The digitally modulatedmodulation data S22 is sent to the laser drive circuit 11, whichmodulates the laser power according to the modulation data S22, andrecords data to the data recording area UD of the target sector on theoptical disc 8. While the data of 16 sectors is the smallest unit usedfor error detection and correction coding, data can be recorded insector units because each sector has a unique address.

The operation for reproducing data is described briefly next. When datais reproduced, the control CPU 18 sends the target track for datareproduction to the focus tracking controller 17, and the focus trackingcontroller 17 tracks the light beam from the optical head 10 to thetarget track. As during recording, a digital read signal 20 is generatedfrom the light reflected from the optical disc 8, and the target sectoris detected by the modulator/demodulator 12. The modulator/demodulator12 digitally demodulates the digital read signal 20 obtained from thedata recording area of the target sector, and supplies the result as thereproduced data to the error detector and corrector 13. The errordetector and corrector 13 begins the error detection and correctionoperation after 16 sectors of reproduction data have been supplied fromthe modulator/demodulator 12. That is, decoding the C1 and C2 errorcorrection codes is repeated to the correction capacity of the code,thereby correcting read errors resulting from foreign matter on therecording surface of the optical disc 8. The corrected data is thenpassed through the interface controller 15 to the host computer.

The above operations are controlled by the control CPU 18 and executedas a single continuous operation. It should be noted that description ofa timing control circuit and other components common to a conventionalrecording and reproducing apparatus for an optical disc recording mediumis omitted in FIG. 5 and the above description.

FIG. 6 is an illustration of a substitution process according to thepresent invention adapted to a linear replacement type sectorsubstitution process. As described with reference to FIG. 2, data isrecorded to a data sector area ADS provided in each zone ZN in thelinear replacement method, and the data intended for recording to adefective sector is recorded to a spare sector area ASS.

What occurs when a single unit of error detection and correction codeddata is recorded to 16 sectors from sector S0 to S15 is consideredbelow. Whether recording was accomplished normally or not is determinedby detecting address reproduction errors during recording, or by averification process, that is, by reproducing data after it is recordedto determine whether the data can be normally reproduced. It is assumedbelow that a recording error was detected by this verification processin sector S2, that is, that sector S2 is a defective sector.

In this case, sector substitution is not applied to all 16 sectors, thatis, the entire error detection and correction coding unit. Instead, onlythe data D2 that should be recorded to the defective sector S2 isrecorded to an alternate sector, for example alternate sector AS1, inthe spare sector area. ASS. In the subsequent recording and reproducing,the alternate AS1 is always used instead of the defective sector S2.This method whereby alternate data is recorded continuously is known asthe linear replacement method.

Therefore, in the present working example of the invention describedabove, alternate sector recording is applied by sector unit rather thanan masse to the 16 sector unit used for error correction coding. It istherefore only necessary to provide one alternate sector for onedefective sector even when a defective sector is generated, therebyreducing the number of sectors that must be provided as alternatesectors, and enabling an optical disc to be efficiently utilized.

A substitution method based on a verification process whereby recordeddata is immediately reproduced to determine whether data is correctlyrecorded, and a linear replacement operation implemented as described inthe present working example after the verification process, is describednext.

Data is recorded as described above. The recorded data is stored in RAM14 until the verification process described below is completed. Datareproduction in the verification process differs from the normalreproduction operation and in the operation of the error detector andcorrector 13. In the case of reproduction for the verification process,the error detector and corrector 13 only decodes data from a particularsector, and therefore only decodes the C1 code, when decoding the readdata supplied from the modulator/demodulator 12. The C1 code is aReed-Solomon code with an additional 10-byte parity code, enablingcorrection of a maximum 5 bytes at any particular position in the codeword. In the present example, however, the correction operation islimited to 3 bytes, and detection of any error exceeding this levelresults in a recording error determination. A specific sector can beidentified when an error exceeding 3 bytes is detected because the C1code is coded row-wise. Both sectors containing a single error exceeding3 bytes are identified as recording error sectors, and sectors in whichan error occurs in the ID part and in which the address informationcannot be detected during recording, are treated as defective sectors,which are handled by the sector substitution process described below.

In the sector substitution process, the control CPU 18 determines theaddress of an unused alternate sector in the spare sector area ASS whendetection of a recording defect sector is reported by the error detectorand corrector 13. The target track is then extracted from saiddetermined alternate sector address, the focus tracking controller 17 isinformed of the target track as during the recording operation describedabove, and the data is then recorded. Only the data from the defectivesector is recorded when recording to an alternate sector, and recordingis thus controlled by sector unit. A map of information describing therelationship between defective sectors and alternate sectors is alsorecorded at this time to a separate substitution management sector.

By thus applying the sector substitution process to sector units asdescribed above, alternate sectors are not needed for the plurality ofsectors used as the unit for the error correction code when a singlesector is determined to be defective, and it is only necessary toprovide one alternate sector for one defective sector. As a result, thenumber of sectors that must be reserved as alternate sectors can bereduced, and the optical disc can be efficiently utilized as describedabove.

FIG. 7 is an illustration of a substitution process according to thepresent invention adapted to a slipping sector substitution process.Data is also recorded to a data sector area ADS provided in each zone ZNin the slipping method, but the data intended for recording to adefective sector is recorded to the data sector area ADS after thedefective sector. That is, the data sector area ADS is handled in theslipping method as a combination of the above-described data sector area(ADS) and the spare sector area (ASS) of the linear replacement method.

Note that the data verification process is the same in the slippingmethod as in the linear replacement method, and the sector substitutionprocess is therefore described briefly below.

What occurs when a single unit of error detection and correction codeddata is recorded to 16 sectors from sector S0 to S15 is consideredbelow. Whether recording was accomplished normally or not is determinedby detecting address reproduction errors during recording, or by averification process, that is, by reproducing data after it is recordedto determine whether the data can be normally reproduced. It is assumedbelow that a recording error was. detected by this verification processin sector S2, that is, that sector S2 is a defective sector. Instead ofshifting the recording sectors 16 sectors, the unit used for errordetection and correction coding, in this case, the data D2 that shouldhave been recorded to the defective sector S2 is recorded to sector S3,the data D3 that should have been recorded to sector S3 is recorded tosector S4, and so on, shifting each sector after the defective sectorone sector from the intended recording sector. The detected defectivesector S2 is thereafter skipped by this slipping sector substitutionprocess during subsequent data recording and reproducing operations. Asthus described, however, sector skipping is managed in single sectorunits and not in units of sixteen sectors corresponding to the 16 sectorunit of the error correction code. It is therefore only necessary toprovide one alternate sector for one defective sector, thereby reducingthe number of sectors that must be provided as alternate sectors, andenabling an optical disc to be efficiently utilized. It should be notedthat if there are not enough data sectors in the data sector area ADS asa result of alternate sector slipping, data can be recorded to the sparesector area ASS of the linear replacement method.

An advantage of the slipping method is that performance is not degradedby substitution for a defective sector as a result of a seek operationsuch as required in the linear placement method, that is, movement ofthe optical head 10 to the spare sector area ASS of the data sector areaADS during data recording and reproduction. However, the slipping methodis constrained by the need for the following sector to be unused. It istherefore preferable for the slipping method and the linear replacementmethod to be combined during use, that is, for the slipping method to beused for sector substitution when recording the disc for the first timeafter initialization, and for the linear replacement method to be usedfor sector substitution during subsequent recording operations.

It should be noted that error correction is applied only to the C1 codeto identify recording error sectors in the above-described linearreplacement method and slipping method. However, when a CRC or othererror correction code for the sector data 3 is inserted to the sectordata 3, the CRC can be decoded using only data from a particular sector.It is therefore possible to use the CRC for error detection aftercorrecting the C1 code, and to detect recording error sectors based onthis detection result.

As will be known from the above description, the sector substitutionprocess is applied on a single sector basis for an error detection andcorrection coding unit of 16 sectors in both linear replacement andslipping methods in the present invention, thereby consuming feweralternate sectors when a defective sector is detected, and enabling adisc to be efficiently utilized.

The operation of an optical disc recording and reproducing apparatusbased on the present invention as shown in FIG. 5 is described next withreference to FIG. 8. Note that this process starts with a userinstructing a host computer to write data to the optical disc 8 using akeyboard or other input means.

Then, at step #100, the command received from the host computer throughthe input terminal Ti is analyzed by the control CPU 18 to determinewhether the requested process is a write (record) or read (reproduce)operation. If a write command is received, control advances to step#200; if a read command is received, control advances to step #800.

At step #200, the interface controller 15 is controlled for receivingthe data to be recorded from the host computer. After the recording dataS19 is received, the procedure steps to step #300.

The target address, that is, the address of the sector to which the datais to be recorded, is obtained from the primary defect list PDL and thesecondary defect list SDL in step #300, and the procedure steps to step#400. Note that this step is described in further detail below withreference to FIG. 11. Briefly, however, the defective sector addressesPDSA0 to PDSAn contained in the primary defect list PDL, and thedefective sector addresses SDSA0 to SDSAp and alternative sectoraddresses SSSA0 to SSSAp contained in the secondary defect list SDL asdescribed with reference to FIG. 2, are detected.

At step #400, data is recorded to the sector at the target addressdetected in step #300, and the procedure steps to step #500. Note thatthe data recorded in this step #400 is stored in RAM 14 until allprocesses in steps #500, #600, and #700 are completed. Note that thisstep is described in further detail below with reference to FIG. 10.

After confirming whether the recorded sector can be correctlyreproduced, that is, after the verification process of the recordeddata, in step #500, the procedure steps to step #600. Note that datareproduction control of the error detector and corrector in thisverification process step differs from that during normal datareproduction. That is, when the error detector and corrector 13 decodesthe reproduced data from the. modulator/demodulator 12, it decodes onlydata from the same sector, and thus decodes only the C1 code.

As a result of the verification process in step #500, it is determinedin step #600 whether data was normally recorded to the intended targetsector. The C1 code is a Reed-Solomon code with an additional 10-byteparity code, enabling correction of a maximum 5 bytes at any particularposition in the code word. In the present step, however, the correctionoperation is limited to 3 bytes, and detection of any error exceedingthis level results in a recording error determination. That is, a sectorcontaining a single error exceeding 3 bytes is identified as a recordingerror sector, and a sector in which an error occurs in the ID part andin which the address information cannot be detected during recording,are treated as defective sectors. If the verification process returnsyes because data recorded to the target sector cannot be normallyreproduced, that is, the target sector is determined to be a defectivesector, the procedure steps to step #700.

At step #700, a sector substitution process using either a slippingmethod or linear replacement method is performed, and the procedure thenterminates. Note that operation in the slipping method and linearreplacement method is described in further detail below with referenceto FIG. 14 and FIG. 15.

If step #600 returns no, that is, the target sector is not a defectivesector, the procedure ends.

If the received command is determined in the first step #100 to be aread command, the address of the sector from which data is to be read isdetected in step #800 in the same manner as in step #300, and theprocedure steps to step #1000. More specifically, the addresses of thesectors to be accessed in the reproduction sequence are detected basedon the defective sector addresses PDSA0 to PDSAn contained in theprimary defect list PDL, and the defective sector addresses SDSA0 toSDSAp and alternative sector addresses SSSA0 to SSSAp contained in thesecondary defect list SDL.

At step #1000, data is reproduced from the sectors at the targetaddresses detected in step #800, and the procedure steps to step #1100.The operation of this step is described in detail below with referenceto FIG. 9.

At step #1100, the interface controller 15 is controlled to transfer thereproduced data to the host computer, and the procedure then ends.

Operation of the control CPU 18 in the reproduction control step #1000in FIG. 8 is described next with reference to FIG. 9.

At step S1002, the control CPU 18 controls the focus tracking controller17 in a seek operation for moving the optical head 10 to the targettrack associated with the target sector to be read, and the proceduresteps to step S1004. In this seek operation, focus tracking controller17 is controlled to move the optical head 10 to the target trackassociated with the target sector to be read, and track the light beamto the target track.

At step S1004, the address recorded to the ID part of the sector isreproduced by the modulator/demodulator 12. The target sector isdetected by a match between the reproduced address and the address ofthe target sector, and the process then steps to step S1006. Morespecifically, the target sector is detected by means of themodulator/demodulator 12 comparing and matching the address of thetarget sector with the address reproduced from the ID part of the disc.

At step S1006, data is reproduced from the data recording area UD of thedetected target sector, digitally demodulated, and the procedure thensteps to step S1008. The digitally demodulated reproduction data fromthe modulator/demodulator 12 is sent to the error detector and corrector13.

At step S1008, the control CPU 18 controls the error detector andcorrector 13 to correct errors resulting from dust, foreign matter, anddefects on the optical disc 8, and the process then ends. That is, theerror detection and correction code is decoded, error correction isapplied, and the corrected data is stored to the RAM 14.

The operation of the control CPU 18 in the recording control step #400in FIG. 8 is described next with reference to FIG. 10.

At step S402, the control CPU 18 controls the focus tracking controller17 in a seek operation for moving the optical head 10 to the targettrack associated with the target sector to be read, and the proceduresteps to step S404. In this seek operation, focus tracking controller 17is controlled to move the optical head 10 to the target track associatedwith the target sector to be read, and track the light beam to thetarget track.

At step S404, the control CPU 18 controls the error detector andcorrector 13 to error detection and correction code a 16 sector block ofrecording data twice, generating a product code, and the procedure stepsto step S406. During this error detection and correction coding process,the recording data from the host computer is error detection andcorrection coded by the error detector and corrector 13, and the codeddata is stored to the buffer RAM 14.

At step S406, the address recorded to the ID part of the sector isreproduced by the modulator/demodulator 12 and compared with the addressof the target sector to detect the target sector, and the proceduresteps to step S408.

At step S408, the error detection and correction coded data is digitallymodulated by the modulator/demodulator 12, recorded to the datarecording area UD of the detected target sector, and the procedure thenends.

The operation of the control CPU 18 in the target address detection step#300 in FIG. 8 is described next with reference to FIG. 11.

At step S310, the primary defect list PDL recorded to both the lead-inarea LiA and lead-out area LoA is reproduced and stored to the bufferRAM 14. The procedure then steps to step S320.

At step S320 the address is converted for the slipping method based onthe content of the reproduced primary defect list PDL, obtaining asector address PADR based on the primary defect list PDL from theaddress LADR requested by the host. The procedure then steps to stepS330.

At step S330, the secondary defect list SDL recorded to both the lead-inarea LiA and lead-out area LoA is reproduced and stored to the bufferRAM 14. The procedure then steps to step S340.

At step S340, the address is converted for the linear replacement methodbased on the content of the reproduced secondary defect list SDL,obtaining a target address TADR for reproduction or recording from thePADR address. The procedure then ends.

The operation of the control CPU 18 in step S320 of FIG. 11 whenconverting an address for the slipping method based on the PDL isdescribed further below with reference to FIG. 12.

At step S321, the address of a specified leading sector in the zone ZNwith which the sector of address LADR is associated is detected, andsubstituted for address ZADR. The procedure then advances to step S323.That is, the first address in the zone to which the sector of addressLADR belongs is set as address ZADR. Note that ZADR is uniformlydetermined in each zone according to a specific format.

The defective sector count m, which is the number m (where m is aninteger) of sectors in the list of defective sector addresses stored tothe primary defect list PDL with an address greater than or equal toZADR and less than or equal to LADR, is determined in step S323, and theprocedure steps to step S325. More specifically, the number q ofdefective sectors in the related zone up to the sector of address LADRis determined. As a result, the sector of address LADR is offset thenumber m of defective sectors by the sector unit slipping operation.

At step S325, it is determined whether the defective sector count m is0. If the defective sector count m is not 0, that is, if defectivesectors are present, a no is returned and the procedure steps to stepS327. That is, it is determined, based on the value of the defectivesector count m, whether LADR conversion due to sector slipping isnecessary.

At step S327, LADR+1 is substituted for ZADR, LADR+m is substituted forLADR, and the procedure returns to step S323. That is, ZADR+1 issubstituted for ZADR, and LADR+m is substituted for LADR, fordetermining whether a defective sector is present between the sector ataddress LADR and the offset sector at LADR+m. The steps following thedefective sector detection step S323 are then repeated until at stepS325 m=0.

However, if step S325 returns no, that is, the defective sector count mis 0 and it is thus determined that there are no defective sectors, theprocedure steps to step S329.

At step S329, LADR is substituted for PADR, and the procedure ends. Morespecifically, LADR is directly substituted for PADR because there are nodefective sectors as determined by m=0.

The operation of the control CPU 18 in the linear replacement methodaddress conversion step S340 based on the SDL shown in FIG. 11 isdescribed next with reference to FIG. 13.

In step S341, it is determined whether an address matching the PADRaddress converted according to the primary defect list PDL is stored inthe defective sector addresses stored to the secondary defect list SDL.If the result is no, that is, if the same address is not stored in thesecondary defect list SDL, the procedure steps to step S345.

At step S345, the PADR address is directly substituted for the recordingand reproduction target sector address TADR, and the procedure ends.

If step S341 returns yes, that is, if the PADR address is recorded as adefective sector address in the SDL, the procedure steps to step S343.

At step S343, the corresponding alternate sector address is substitutedfor TADR, and the procedure ends.

The operation of the control CPU 18 when the sector substitution processstep #700 in FIG. 8 is applied using the slipping method is describednext with reference to FIG. 14.

At step S701, the data stored to the defective sector is shifted to thenext sector and recorded in a slipping recording operation, and theprocedure steps to step S703. That is, when the sector substitutionprocess is performed in sector units using the slipping method, the datafrom the defective sector is alternately recorded to the next sectorafter the defective sector.

The verification process performed in step S703 reproduces the datarecorded to the slip-recorded sector to confirm that the data iscorrectly recorded, and then the procedure steps to step S705. Note thatthe verification process performed in this step is the same as thatperformed in step #500 in FIG. 8.

Step S705 is a defective sector discrimination step whereby it isdetermined whether the sector to which data is shifted from a defectivesector by the slipping method is itself a defective sector. As such, theoperation of step S705 is the same as that of step #600 in FIG. 8. A nois returned when the sector is normally recorded by the slipping method,and the procedure steps to step S707.

The address of a newly detected defective sector is appended to the endof the PDL in step S707, and then the procedure steps to step S709.

The updated PDL is then multi-recorded to DMA1, DMA2, DMA3, and DMA4 instep S709, and the procedure ends.

If at step S705 a yes is returned because the sector was not normallyrecorded by the slipping method, the procedure loops back to step S701.In other words, whether the alternatively recorded sector could becorrectly recorded or not is determined by the verification process stepS703 and the defective sector discrimination step S705, and the sliprecording step S701, verification process step S703, and defectivesector discrimination step S705 are repeated until normal recording issuccessfully confirmed.

If the sector is normally recorded, the address of any newly occurringdefective sector is appended to the end of the PDL in the PDLregistration step S707. The PDL updated in the PDL registration step isthen recorded multiple times, that is, to the DMA1, DMA2, DMA3, and DMA4of the lead-in area LiA and lead-out area LoA.

The operation of the control CPU 18 when the sector substitution processstep #700 in FIG. 8 is applied using the linear replacement method isdescribed next with reference to FIG. 15.

At step S711, the data stored to the defective sector is replacementrecorded to an alternate sector in the spare sector area ASS at thelowest unused address in the same zone ZN, and the procedure steps tostep S713.

The verification process performed in step S713 reproduces the datarecorded to the replacement recorded sector to confirm that the data iscorrectly recorded, and then the procedure steps to step S715. Note thatthe verification process performed in this step is the same as thatperformed in step #500 in FIG. 8.

Step S715 is a defective sector discrimination step whereby it isdetermined whether the sector to which data is recorded from a defectivesector by the replacement method is itself a defective sector, and isthe same as step #600 in FIG. 8. A no is returned when the sector isnormally recorded by the replacement method, and the procedure steps tostep S716.

At step S716, the address of the defective sector to which recording wasfirst attempted, and the address of the corresponding alternate sector,are inserted as a pair to the secondary defect list SDL in ascendingorder at the address of the defective sector. The procedure then stepsto step S718.

The updated secondary defect list SDL is then multi-recorded to DMA1,DMA2, DMA3, and DMA4 in step S718, and the procedure ends.

When the sector substitution process is implemented in sector unitsusing a linear replacement method, the control CPU 18 alternatelyrecords the data from the defective sector to an unused alternate sectorin the replacement recording step S711. Next, it determines whether thealternately recorded sector was correctly recorded in the verificationprocess step S713 and the defective sector discrimination step S715, andthe replacement recording step S711, verification process step S713 anddefective sector discrimination step S715 are repeated until normalrecording is successfully confirmed.

If the sector is normally recorded, the address of the defective sectorto which recording was first attempted, and the address of thecorresponding alternate sector, are inserted as a pair to the secondarydefect list SDL in ascending order at the defective sector address inthe SDL registration step S716, and the procedure ends.

Finally, the updated secondary defect list SDL is recorded multipletimes, that is, to the DMA1, DMA2, DMA3, and DMA4 of the lead-in areaLiA and lead-out area LoA in the SDL registration step S718.

A substitution process whereby one alternate sector is consumed for onedefective sector is thus accomplished using a slipping method and alinear replacement method.

ABILITY FOR APPLICATION IN INDUSTRY

As described above, a recording defect substitution method for adisc-shaped recording medium, and a disc-shaped recording mediumrecording and reproducing apparatus according to the present inventionminimize the alternate area for defective sectors in high recordingdensity disc-shaped recording media in which burst-mode recording andreproduction errors occur easily, and can thereby highly efficiently usethe recording area of a disc-shaped recording medium.

What is claimed is:
 1. A disc-shaped recording medium recordingapparatus for recording data in a disc-shaped recording medium (8)having a plurality of sectors, said disc-shaped recording mediumrecording apparatus comprising: a coding means (13) for coding the datainto a product code having error detection and correction coded dataaligned in both row and column directions, and segmenting said productcode with error detection and correction coded data into a plurality ofsegment coded data units; means (10, 11, 12) for recording said productcode in a plurality of sectors, each segment coded data unit beingrecorded to a sector in a first recording area (ADS) of the disc-shapedrecording medium (8); defective sector discrimination means (#500, #600)for determining whether a sector is a defective sector by reproducingsaid segment coded data unit recorded in said sector; and defectivesector substitution means (#700), which, in the case where said sectoris determined to be a defective sector, records said segment coded dataunit which was intended to be recorded in said defective sector to analternate sector in a second recording area (ASS) provided on saiddisc-shaped recording medium (8).
 2. The disc-shaped recording mediumrecording apparatus according to claim 1, wherein the defective sectordiscrimination means (#500, #600) determines a sector to be a defectivesector when address information (ID) pre-recorded to said sector cannotbe correctly reproduced.
 3. The disc-shaped recording medium recordingapparatus according to claim 1, wherein the defective sectordiscrimination means (#500, #600) determines a sector to be a defectivesector by decoding only the error detection and correction code (C1),which can be decoded using only data recorded to said sector.
 4. Thedisc-shaped recording medium recording apparatus according to claim 2,wherein the defective sector discrimination means (#500, #600)determines a sector to be a defective sector when data recorded to saidsector cannot be correctly reproduced.
 5. The disc-shaped recordingmedium recording apparatus according to claim 1, wherein for recordingdata in and after a defective sector, the defective sector substitutionmeans (#700) alternately records to an alternate sector only data thatshould be recorded to said defective sector.
 6. The disc-shapedrecording medium recording apparatus according to claim 1, wherein thesecond recording area (ASS) is provided separated a specific number ofsectors or more from the first recording area (ADS).
 7. The disc-shapedrecording medium recording apparatus according to claim 1, wherein thesecond recording area (ASS) is contiguous to the first recording area(ADS).
 8. A disc-shaped recording medium recording method for recordingdata in a disc-shaped recording medium (8) having a plurality ofsectors, said disc-shaped recording medium recording method comprising:coding the data into a product code having error detection andcorrection coded data aligned in both row and column directions;segmenting said product code with error detection and correction codeddata into a plurality of segment coded data units; recording saidproduct code in a plurality of sectors, each segment coded data unitbeing recorded to a sector in a first recording area (ADS) of thedisc-shaped recording medium (8); determining (#500, #600) whether asector is a defective sector by reproducing said segment coded data unitrecorded in said sector; and in the case where said sector is determinedto be a defective sector, recording said segment coded data unit whichwas intended to be recorded in said defective sector to an alternatesector in a second recording area (ASS) provided on said disc-shapedrecording medium (8).
 9. The disc-shaped recording medium recordingmethod according to claim 8, wherein a sector is determined to be adefective sector when address information (ID) pre-recorded to saidsector cannot be correctly reproduced.
 10. The disc-shaped recordingmedium recording method according to claim 8, wherein a sector isdetermined to be a defective sector by decoding only the error detectionand correction code (C1), which can be decoded using only data recordedto said sector.
 11. The disc-shaped recording medium recording methodaccording to claim 9, wherein a sector is determined to be a defectivesector when data recorded to said sector cannot be correctly reproduced.12. The disc-shaped recording medium recording method according to claim10, wherein for recording data in and after a defective sector, onlydata that should be recorded to said defective sector is recorded to analternate sector.
 13. The disc-shaped recording medium recording methodaccording to claim 9, wherein the second recording area (ASS) isprovided separated a specific number of sectors or more from the firstrecording area (ADS).
 14. The disc-shaped recording medium recordingmethod according to claim 8, wherein the second recording area (ASS) isprovided contiguously to the first recording area (ADS).